diff --git a/__test__/Polyline/__snapshots__/offset3.test.ts.snap b/__test__/Polyline/__snapshots__/offset3.test.ts.snap
index 5721f151f..038901f05 100644
--- a/__test__/Polyline/__snapshots__/offset3.test.ts.snap
+++ b/__test__/Polyline/__snapshots__/offset3.test.ts.snap
@@ -7,3 +7,11 @@ exports[`圆弧被压扁时 2`] = `"1260.08301"`;
 exports[`圆弧被压扁时2 1`] = `1`;
 
 exports[`圆弧被压扁时2 2`] = `"2922.62557"`;
+
+exports[`由于点在线内错误导致的偏移错误 1`] = `1`;
+
+exports[`由于点在线内错误导致的偏移错误 2`] = `"6230.72714"`;
+
+exports[`由于点在线内错误导致的偏移错误 3`] = `1`;
+
+exports[`由于点在线内错误导致的偏移错误 4`] = `"6180.46135"`;
diff --git a/__test__/Polyline/offset3.test.ts b/__test__/Polyline/offset3.test.ts
index 7a8287493..c3d1ea39a 100644
--- a/__test__/Polyline/offset3.test.ts
+++ b/__test__/Polyline/offset3.test.ts
@@ -44,3 +44,13 @@ test('圆弧被压扁时2', () =>
 
     testOffset(pl, -15);
 });
+
+test('由于点在线内错误导致的偏移错误', () =>
+{
+    let pl = loadFile(
+        [2, "Polyline", 8, 2, 0, false, 0, 7, 0, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], 0, 0, true, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], 0, 2, 12, [964.1726917869288, 2166.0000000029972], 0, [81.82735810056852, 2166], 0.3415531568154667, [40.20999509376975, 2133.8164270510624], 0.05489447350760577, [0.000024946672056103125, 1768.2989623206213], 0, [0.00002495866783647216, 437.7012596801617], 0.04953932502193947, [40.21532578137385, 32.163083246120095], 0.3414157136434686, [81.8273581160156, 2.9976945370435715e-9], 0, [964.172691799029, 0], 0.3414157138387472, [1005.7847240515422, 32.16308280570047], 0.049539325021327685, [1046.0000249832037, 437.7009488243086], 0, [1046.0000249590144, 1768.2987401249993], 0.054894473508189726, [1005.7900548890677, 2133.8164267602974], 0.3415531571190822, true, "Polyline", 8, 2, 0, false, 0, 7, 0, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], 0, 0, true, [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], 0, 2, 10, [1050.0000249590144, 1768.298295468967], 0, [1050.0000249836708, 1768.2987401250723], 0.0548944072866294, [1009.6943012621955, 2134.6864039197217], 0.008757597397914658, [1009.6614374965075, 2134.8226060220663], 0.3415531571190834, [964.1726917869152, 2170.0000000029972], 0, [81.82735810055493, 2170], 0.3415531568154657, [36.33861249020625, 2134.8226063277452], 0.008757508805047694, [36.30574877822974, 2134.6864044689264], 0.054894407325456196, [-3.999975077955014, 1768.2989623205858], 0, [-3.99997505332794, 1768.2985179293778], 0, false]
+    )[0] as Polyline;
+
+    testOffset(pl, 4);
+    testOffset(pl, -4);
+});
diff --git a/src/GraphicsSystem/OffsetPolyline.ts b/src/GraphicsSystem/OffsetPolyline.ts
index f787208d7..12a8d92d5 100644
--- a/src/GraphicsSystem/OffsetPolyline.ts
+++ b/src/GraphicsSystem/OffsetPolyline.ts
@@ -1,4 +1,6 @@
+import { debug } from "request-promise-native";
 import { Box3, Matrix4, Vector3 } from "three";
+import { TestDraw } from "../Add-on/test/TestUtil";
 import { arrayLast } from "../Common/ArrayExt";
 import { ConverCircleToPolyline } from "../Common/CurveUtils";
 import { Status } from "../Common/Status";
@@ -66,7 +68,7 @@ class CurveTreeNode
                 if (cus.length === 0)
                 {
                     let p = this.curve.GetPointAtParam(0.5);
-                    if ((contour.Curve.PtInCurve(p) && !contour.Curve.PtOnCurve(p)))
+                    if (box.containsPoint(p) && (contour.Curve.PtInCurve(p) && !contour.Curve.PtOnCurve(p)))
                         this.children = [];
                 }
                 else
@@ -75,7 +77,7 @@ class CurveTreeNode
                     for (let c of cus)
                     {
                         let p = c.GetPointAtParam(0.5);
-                        if (CurveIsFine(c) && (!contour.Curve.PtInCurve(p) || contour.Curve.PtOnCurve(p)))
+                        if (CurveIsFine(c) && (!(box.containsPoint(p) && contour.Curve.PtInCurve(p)) || contour.Curve.PtOnCurve(p)))
                             this.children.push(new CurveTreeNode(c));
                     }
                     if (this.children.length === cus.length)